I have a five year old miniature schnauzer who was well socialised in puppyhood and cheerful with other dogs. Over the last year she has begun to growl and bark at people she doesn't recognise - at the door, in the street through the window, on the beach - everywhere. Now it's a major problem because she's growling at the nurses in our parent's nursing home, and that is a serious problem! She is an only dog in a empty-nest household with a cat for company, and gets on well with the cat. She never snaps, and when people actually get closer she will always greet them happily. She is also irritablw with other dogs, and acts defensively when approached by other people with dogs in tow. Won't play with them. Can anyone tell us what's going on in her mind, and how to help?